vector arr = { 6, 3, 5, 2, 8 };
vector::iterator itr = std::find(arr.begin(), arr.end(), elem);

if (itr != end(arr)) {
    cout << "Element " << elem << " is present at index " << distance(arr, itr) << " in the given array";
}
else {
    cout << "Element is not present in the given array";
}